Qantas A380 uncontained #2 engine failure

[ChristiaanJ]

Originally Posted by Teddy Robinson

... but that was an engineered failure of an N1 blade on a static rig...

Thanks Teddy, some common sense at least.
Shedding a blade, with all the collateral damage, is about the "worst case" that can be contained.
The tests are set up that way, a "worst case" of engine running conditions is selected, and a blade is 'explosively' removed during the test.
Not done every day, since each test does enough damage to pretty well ruin the engine under test.
Blade failures happen, it will lead to an IFS and it usually doesn't even make the papers.

arearadar,
I somewhat agree.... I expected some of the more 'weird and wonderful' posts to be moderated.

CJ

[fdr]

fuel tank supposition?

2 holes, minimum.

still image in flight shows fuel venting not from the jettison system

video of approach, touchdown and landing rollout from inside and abaft wing (shows the partial spoiler deployment post touch down...) has venting fluid over the inner area of the flaps, that is not characteristic of atmospheric moisture (continues after touchdown...)

2 holes or more exit, therefore entry, #2 Tank. Question is if it went in via the lower skin or the spar. Spar = expensive. (skins alone are not going ot be cheap)


FDR


PS crew did a nice job.

[simfly]

The moisture on the videos after touchdown could be mositure off the runway if it was wet, being kicked up by the wheels. Looking at the photos of the top surface holes, it does look like something leaked out of them, theres a stain behind them but I'm not expert enough to say what, if anything, it could have been.

[Boomerang_Butt]

Here's something new:

Three senior captains on the flight found themselves deluged with 54 error messages as the plane's sophisticated computers registered the extent of the damage to the aircraft.

Not a slack day at work, that's for sure!

(From The Australian online)

[chase888]

A lot of pages already and I hope I did not miss anything regarding the reported overspeed warning 2 days prior.

I am in power generation, and I can assure you that any overspeed indication results in IMMEDIATE shutdown of that machine, never to run again until the reason has been determined and fixed.

If this report of overspeed warnings is true, then the ops manual and MEL needs revising.

Overspeed itself usually involves a relatively simple fix, rarely a design issue involved.

Two cents worth from a landlubber!

[winglets747]

Fuel tank

I was considering the scenario had shrapnel gone through a fuel tank and stumbled on this:

The Airbus A380 will not feature fuel tank inerting, but rather a comprehensive effort to minimize ignition sources. National Transportation Safety Board (NTSB) officials say the system safety assessments upon which the fuel system for the A380 is predicated, with the focus on ignition sources, is an incomplete approach.

NTSB Disappointed That A380 Fuel Tanks Will Not Be Inerted | Air Safety Week | Find Articles at BNET

The rebuff was:

"Fuel tank inerting technology separates nitrogen and oxygen from engine bleed-air and uses the nitrogen to inert the tank, or make it less flammable. The technology to use the separated oxygen for additional cabin air has apparently become too cumbersome; therefore, the oxygen by-product will be dumped overboard. The initial passenger versions of the A380 will not have a center fuel tank; therefore, inerting will not be necessary."

Concerns about NDT of new Airbus A380

Thoughts? Had shrapnel gone through a fuel tank, would inerting have lessened any damage?

[wiggy]

chase

If this report of overspeed warnings is true, then the ops manual and MEL needs revising

There have been mention of this but it has never been made clear wheter the aircraft had a history of turbine overspeeds or if the problem was that the Turbine Overspeed warning system was inop.

[trickii]

Uncontrolled Engine failure theory A380

This engine is prity much a well tested product from the manufacturers..this is a film on containment of fan blade failure by Rolls Royce..looks convincing to me?

YouTube - A380 Blade Off Test

Roll Royce engineering monitor the preformance of all of their engines in service and will already know the issues within minutes in the UK.

My guess is that they will concentrate on maintence proceduers and history for the ansawers....

Do watch this film!

[MathFox]

Fuet tank inertion

The Airbus A380 will not feature fuel tank inerting

I am sceptical about the value of fuel tank inertion, several reasons:

1. Keeping the (expelled) oxygen out requires that the wall of the fuel tank remains gas-tight... As pictures show, engine parts can blow a hole through the wall of the fuel tank. Also, pretty often in (rejected) take off and landing incidents the fuel tanks get ruptured enough for inertion to be ineffective.
2. Jet fuel isn't that flamable. It should be heated to about 50°C to be able to form an flamable (explosive) fuel-air mixture. Hotter at altitude. Keeping the fuel cool (but not BA38 freezing) would be enough to prevent a fire hazard.

[sharksandwich]

Sharksandwich is an idiot
Fatal Plane Crash Rate for Selected Airliner Models

This is an engine issue versus an airframe manufacturer issue. Airbus does NOT equal RollsRoyce

I do not have a problem with the idiocy reference.
But what I intended to say is, compared with Boeing 737s and 747s, one would expect problems with a 40 year old design which has been up-dated.
But Airbus was designed this century, with 40 years of technological advance that was not available to designers and engineers in the 1960s and 70s.
So why do they fail with depressing regularity? That was the only point I was trying to make.

[fdcg27]

Uncontained failure

Uncontained engine failures are rare, and the Trent is a mature design, which some carriers prefer to anything GE or Pratt.
This is a random event caused by either a manufacturing defect, or a maintenance error.
I am a fan of neither Airbus nor Rollers, since I own shares in both GE and Boeing.
However, I would not hesitate to fly in any Airbus, nor would I question either the reliablity or durability of any Rolls-Royce gas turbine.
A random event, in other words, not a systemic problem.
Anyway, the aircraft landed with no injuries to anyone, so even in a potentially bad situation, everything worked out well, as it is intended to.
Everything flight critical is either fail-safe or redundant, so the airplane landed, and everyone aboard walked away.
A happy ending, not the ragged edge of disaster portrayed by Katie and some ex-NTSB blimp I saw on the network news.

[barrymung]

As others have said most likely a random, albeit unfortunate, failure.

What for Airbus and the A380 now? Obviously, the image of the A380 and Rolls is now severely damaged and the 'feel' created by the reports on the TV news tonight were almost of "Comet-esque" proportions.

How to restore confidence in the flying public?

[barrymung]

Question: What is the failure rate of Trent engines, versus the failure rate of this particular model?

Given the number of hours the entire A380 fleet has flown, surely a single failure if this type is not uncommon?

What I'm getting at is that this particular engine is no less reliable than any other, just that the press are making an example of it, 'cos the plane is new.

[BigHitDH]

Repair...

I'm wondering how easy it might be to effect a repair on the upper wing skin. The A380 uses a 111ft long, 4000kg single upper wing skin, the biggest ever. It'll be interesting to see what solutions the engineers at Filton have for this one.

[njfly]

Bralo20

Quote:

"AR-AFFF foam (alcohol-resistant film forming fluoroprotein)"

is not correct.

Correct acronyms are as follows:

AR-AFFF alcohol-resistant aqueous film-forming foam

AR-FFFP alcohol-resistant film-forming fluoroprotein foam

Are you sure AR-AFFF and/or AR-FFFP are used in aircraft fire fighting equipment?

[Whirlybird1]

ATA 72- Pressure coupling splines. These were advised to be a potential problem and the most likely cause..

Andy.

[fdr]

HYD or FUEL

Quote:
Appears to have been a fuel tank leak from the wing
Fuel or hydraulic fluid? BILLS

at 5000 PSI, the system quantity is gone in seconds not hours.

Equally, the extent of vapor in flight, and 1.5 hrs later on approach and landing is well in excess that of a hyd system contents being atomised. After landing the volume remaining in the tank (having jettisoned) would be primarily inboard in the tank, and the penetrations appear to be on the outer extent of the tank, the tank having a substantial vertical level difference between outer and inner sections. Little or no leaking may have been exhibited on the ground without flow over the section.

Fragmentation of a turbine disc by itself does not necesarily provide a ready fuel ignition source, when the tank doesn't have a high vapor content. (UA800 had a relatively unusual but not uncommon F/A stoichiometric ratio, [~1.2% fuel by volume or partial pressure] and a high temperature, and still required a high energy source as per 25.981, 26.31-39 reqts related to flammability exposure levels as per appendix N of CS25 amd6).

FDR

[Gegenbeispiel]

308 tickii

A turbine (HP or IP) disc is not a fan blade, so the containment issues are quite different. It's very hot, not cold. It's much bigger. It's heavier. It's made of metal, not composite. It was probably spinning very much faster. It's in a different part of the engine and has to be contained, if at all, by different parts.

[nedmon]

Turbine discs are made from steel forgings and are rigorously tested before and during the engine manufacturing process such that a catastrophic burst failure in operation would be most unlikely.

An overspeed is different. Any turbine disc will will burst is a sufficiently high rotational speed is attained.

Look at an image of the Trent engine and you can see that the biggest and consequently highest stressed disc is at the rear of the engine.

And it looks like this is the disc that failed.

[Flightsimman]

Looks like Father Christmas has visited Batam early this year!